The goal of this application is to acquire a highly sensitive mass spectrometer with high mass accuracy and high resolution for the proteomic analysis of complex biological samples. The instrument is needed to identify and quantify posttranslationally modified amino acids, sequence biological peptides, and to improve significantly our confidence in identifying a peptide or protein based on a single tandem mass spectrum. The mass spectrometer will be coupled to a nanoliter-flow liquid chromatography system via a nanoelectrospray ionization source to fractionate and analyze low-abundance peptides or proteins from a variety of biological samples. The nanoLC-mass spectrometry system will be located in Vanderbilt University's Mass Spectrometry Resource Center to primarily support the increasing demands for high-end mass spectrometry from NIH- supported laboratories. This application seeks to capitalize and leverage the tremendous proteomics expertise at Vanderbilt University by providing additional access to high-end mass spectrometry technology to research laboratories involved in biomedical research. Research projects under investigation include the immune response, cancer biology, viral pathogenesis, vaccine development, biomarker discovery, transcriptional regulation, RNA processing, and translational control. PUBLIC HEALTH RELEVANCE: Proteomics is playing an increasingly important role in understanding the causes of many human diseases including cancer, inflammation, arthritis, and diabetes. The requested LTQ Orbitrap hybrid FT mass spectrometry system will provide access to high-end mass spectrometry for NIH-funded research groups studying a variety of biomedical research issues. Projects under investigation include the immune response, cancer biology, viral pathogenesis, vaccine development, biomarker discovery, transcriptional regulation, RNA processing, and translational control.